Ecology and Population Structure of Sitona weevils (Coleoptera: Curculionidae) in Legume Cropping Systems

Abstract

Sitona weevils (Coleoptera: Curculionidae) are economically important pests of legume crops, causing damage through adult foliar feeding and larval root infestation that negatively affect plant growth, nitrogen fixation, and crop productivity. Understanding the ecology and population structure of Sitona species is essential for developing effective pest management strategies in legume-based agricultural systems. The present study was conducted to investigate the seasonal ecology, distribution patterns, and population structure of Sitona weevils in major legume cropping systems. Field surveys and sampling were carried out across different cultivation sites during multiple growing seasons to assess species composition, population density, developmental stages, and habitat associations. Environmental factors including temperature, humidity, soil characteristics, and crop growth stage were also recorded to determine their influence on weevil population dynamics. Morphological identification and statistical analyses were used to evaluate species diversity and spatial distribution patterns within the agroecosystem. The results revealed considerable variation in Sitona population abundance across different legume crops and environmental conditions. Population density increased significantly during favorable climatic periods characterized by moderate temperature and adequate soil moisture. Aggregated distribution patterns were observed in most fields, indicating localized colonization and feeding behavior of the weevils. Several Sitona species were identified, with dominant species exhibiting strong adaptation to specific legume hosts. The study also demonstrated that crop type and environmental variables significantly influenced population structure and seasonal occurrence of the pest. The findings provide important ecological insights into the behavior and distribution of Sitona weevils in legume production systems. Understanding the population dynamics and habitat preferences of these pests is essential for improving monitoring programs and developing integrated pest management strategies aimed at minimizing crop damage and enhancing sustainable legume cultivation.